1. Field of the Invention
The present invention relates to a light emitting device and an apparatus comprising the same, and more particularly, to a white organic light emitting device having high light luminous efficiency and low power consumption, and a display apparatus and a lighting apparatus comprising the white organic light emitting device.
2. Description of the Related Art
Organic light emitting devices (OLEDs) are emissive display devices that use light generated from combinations of electrons and holes, which are supplied to a fluorescent or phosphorus organic compound thin film (hereinafter, an organic thin film). Generally, an OLED has a structure in which an anode, a hole transporting layer, a light emitting layer, an electron transporting layer, and a cathode are sequentially formed on a substrate.
A white OLED can emit white light, and can be used for various purposes such as a paper-thin light source, a backlight of a liquid crystal display apparatus, or a full color display apparatus that employs color filters.
Methods of manufacturing the white OLED can be divided into two types according to the method of manufacturing a light emitting layer. The first type refers to methods of manufacturing the light emitting layer in a single layer (a first conventional method). The second type refers to methods of manufacturing the light emitting layer in multiple layers (a second conventional method).
The first conventional methods include a method of doping red, green, and blue dopants in one host and a method of doping red and green dopants in a blue host. In this case, however, it is difficult to block an energy transfer between dopants, and thus, the luminous efficiency of the white OLED is reduced although the doping concentration of the dopants is controlled.
In the second conventional methods, a stacked light emitting layer is formed by stacking a red light emitting layer, a green light emitting layer, and a blue light emitting layer. In this case, however, it is not easy to obtain a high luminous efficiency and a uniform spectrum of the three primary colors due to difficulties in dispersing excitons in each of the light emitting layers, and a large energy transfer occurs between the light emitting layers.